Passive optical network, equipment and method for supporting multicast service

An Optical Line Terminal (OLT), comprising:

• a multicast data transmission pre-processing module, configured to modulate multicast service data onto an optical signal having a first wavelength;
• n modulators, each of the n modulators configured to modulate downstream unicast data to be transmitted to an ONU onto an optical signal having one of n wavelengths, wherein the n is a natural number that is larger than or equal to 1 and the n wavelength is different from the first wavelength;
• a multiplexer/demultiplexer, configured to multiplex the modulated optical signal from the multicast data transmission pre-processing module and the modulated optical signals from the n modulators.

An apparatus, comprising:

• a coarse wavelength demultiplexer (CWDM), configured to divide a channel of received optical signal into a plurality of channels of optical signals, the wavelengths of the channel of received optical signal comprising a specific wavelength for carry multicast service data and a first wavelength for carrying downstream unicast data, the plurality of channels of optical signals comprising a channel of optical signal having a specific wavelength for carrying multicast service data and a channel of optical signal having other different wavelength from the specific wavelength for carrying downstream unicast data;
• a splitter with a splitting ratio of 1:a, configured to split the channel of optical signal having the specific wavelength for carrying multicast service data from the CWDM by performing power allocation, into a portions, each of the a portions of optical signals having the specific wavelength for carrying multicast service data being output to a corresponding ONU.

A method for implementing service in a Passive Optical Network (PON), comprising:

• an Optical Line Terminal (OLT) transmitting an a channel of downstream optical signals having at least two wavelengths to a multiplexer/demultiplexer, a first downstream optical signal having a first wavelength of at least two wavelengths being modulated with downstream unicast data and a second downstream optical signal having a specific wavelength of the at least two wavelengths being modulated with multicast service data;
• n ONUs receiving optical signals from the multiplexer/demultiplexer, wherein the optical signals received by each of at least two of the n ONUs comprise an optical signal having the specific wavelength modulated with multicast service data, and the ONU which receives the optical signals having the specific wavelength modulated with multicast service data recovers the multicast service data.